Indoor air quality in residential buildings has been attracting more attention from the public. Many portable air cleaner products have been developed and are available in the market. Manufactures generally claim that those portable air cleaners can efficiently remove PM2.5 and/or TVOC and can also remove virus from the indoor air. However, no standards are available to have the claimed efficiency comparable and thus unclear effect in applications at homes.

The majority of research and hence the assessment methods and tools for thermal comfort assessment of ventilation systems are not based on findings for natural ventilation solutions and do not take into account the specific characteristics of natural ventilation. This has created a lack of suitable methods for the assessment and performance evaluation of natural ventilation. This paper will focus on the evaluation of assessment methods related to estimating the risk of draught for natural ventilation systems.

This study introduces a novel conceptual design of a mobile DV cooling unit that is aimed to support the ventilation and reinforce the thermal stratification in DV rooms. Supplying filtered chilled air from at low height, the portable DV unit (PDV unit) functions as if it is a typical DV diffuser. Moreover, the PDV unit employs heat exhausted from the heat pump to reinforce the temperature gradient by injecting the hot air flow in the upper zone of the room. Utilizing the exhaust air makes the PDV unit entirely ductless which adds to its flexibility placed in to balance the airflow.

Naturally ventilated (NV) buildings, when well designed and operated, can provide adequate indoor environmental quality (IEQ) while reducing the building energy demand. However, in dusty outdoor air, this ventilation technique may increase the penetration of outdoor particulate matter (PM) indoors, leading to adverse health effects. Given the increasing frequency of outdoor dust episodes in Mediterranean climates, an important research question is whether NV buildings can provide adequate indoor air quality (IAQ) during increased outdoor air dust episodes.

Buildings account for 40% of EU energy consumption and 36% of the energy related greenhouse gas emissions at present. Consequently, the net zero target set by Energy Performance of Building’s Directive by 2050 for building stock is ambitious to achieve. The often default design choice to adopt mechanical cooling in non-domestic buildings highlights the lack of robust decision support tools or frameworks available to designers to properly evaluate ventilative cooling as a realistic alternative.

Most New Zealand schools are designed to be naturally ventilated, using openable windows (Ministry of Education Design Quality Standard Guidelines). Furthermore, they must meet the New Zealand Building Code Clause G4 - Ventilation. Clause G4 requires the “net openable area of windows in a classroom to be no less than 5% of the combined habitable floor area to achieve sufficient ventilation”. Although they are designed to code, there is no end-user operational or systems requirement for them to be opened.

As a result of the new initiatives and regulations towards nearly zero energy buildings, designers are more frequently exploiting the cooling potential of the climate to reduce overheating and improve indoor well-being of people. At early stage of design, climate analysis is particularly useful for determining the most cost-effective passive cooling methods, such as ventilative cooling. However, besides the external climate conditions, building energy uses are characterized by occupancy pattern and needs, envelope characteristics and internal loads.

In recent years, naturally ventilated glass façades have become a common feature in the design and retrofit of large-scale non-residential buildings, integrating architectural aesthetics and energy efficiency. These façade systems are complex and multifaceted. Thus, introducing them in buildings poses many challenges from economic, engineering, health and behavioural perspectives that can reduce optimal building performance. Building occupant behaviour and preferences are important contributors to the gap between the predicted and actual building energy performance.

With rising insulation standards and air tightness in buildings, the use of mechanical ventilation becomes more relevant. In this context, energy recovery offers a significant contribution to the decarbonisation of building operations. Heat recovery systems are widely spread in residential ventilation. Moreover, enthalpy exchangers recovering sensible and latent heat have an increasing share of use in residential ventilation, especially in cold climates, as they not only reduce the energy demand but also increase the indoor air humidity in winter seasons.

Literature on the in-situ performance evaluation of Mechanical Ventilation with Heat Recovery (MVHR) in low-carbon social housing suggests that they can maintain a healthy ventilation rate in bedrooms in the UK. However, issues with noise and draught have been reported frequently. These issues may affect the sleep quality of occupants and have a detrimental effect on health and wellbeing. This research aims to present a quantification of these issues by carrying out detailed monitoring and evaluation at two case study sites in Wales, UK.